A rotor blade of a compressor made from a titanium alloy is known from U.S. Pat. No. 5,063,662. Blades and vanes which are based on titanium offer the advantage of a considerable weight saving compared, for example, to blades or vanes made from steel. However, titanium alloys are almost impossible to cast. A forged blade or vane cannot be of hollow design, which means that the weight saving is wiped out again. One possible way of producing a blade or vane of this type is to bond together two halves. In this case, the halves are joined to one another at a high pressure and a high temperature. Then, the blade or vane is twisted. To maintain its shape, a gas is fed to the hollow interior of the blade or vane under a high pressure. The way in which a gas feed line is introduced into the blade or vane root of a titanium blade or vane forms the subject matter of U.S. Pat. No. 5,448,829.
Furthermore, U.S. Pat. No. 5,516,593 reveals a titanium turbine blade or vane produced from two halves by means of a diffusion bonding process. Opposite grooves running in the longitudinal extent of the blades or vanes are provided in the region of the leading edge and trailing edge on the contact surfaces of the two halves which are in contact with one another. During the bonding process, the cavities formed by the grooves serve as a yielding space for the excess material which would otherwise lead to buckling at the flow surface of the turbine blades or vanes.